linux-kernel - Re: [PATCH] pinctrl/amd: poll InterruptEnable bits in enable

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Date:   Wed, 28 Mar 2018 10:49:49 +0530
From:   "Shah, Nehal-bakulchandra" <Nehal-Bakulchandra.shah@....com>
To:     Linus Walleij <linus.walleij@...aro.org>,
        Daniel Kurtz <djkurtz@...omium.org>,
        Shyam Sundar S K <Shyam-sundar.S-k@....com>,
        Ken Xue <Ken.Xue@....com>
Cc:     adurbin@...omium.org,
        "open list:PIN CONTROL SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] pinctrl/amd: poll InterruptEnable bits in enable_irq

Hi

On 3/26/2018 2:42 PM, Linus Walleij wrote:
> On Mon, Mar 12, 2018 at 5:45 PM, Daniel Kurtz <djkurtz@...omium.org> wrote:
> 
>> In certain cases interrupt enablement will be delayed relative to when
>> the InterruptEnable bits are written.  One example of this is when
>> a GPIO's "debounce" logice is first enabled.  After enabling debounce,
>> there is a 900 us "warm up" period during which InterruptEnable[0]
>> (bit 11) will read as 0 despite being written 1.  During this time
>> InterruptSts will not be updated, nor will interrupts be delivered, even
>> if the GPIO's interrupt configuration has been written to the register.
>>
>> To work around this delay, poll the InterruptEnable bits after setting
>> them to ensure interrupts have truly been enabled in hardware before
>> returning from the irq_enable handler.
>>
>> Signed-off-by: Daniel Kurtz <djkurtz@...omium.org>
> 
> Patch applied.
> 
> I see the AMD people were not on CC so adding them here so they can
> say if there is any problem with the approach.
> 
> Daniel: maybe you should consider listing yourself as comaintainer of this
> driver?
> 
> Yours,
> Linus Walleij
> 

Looks good. 

Regards
Nehal Shah